Alabagrus Stigma, Sugarcane Borer Red-Tailed Braconid (Hymenoptera: Braconidae) Ilgoo Kang, Joseph Mccarthy, Forest Huval and Chris Carlton
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Alabagrus stigma, Sugarcane Borer Red-Tailed Braconid (Hymenoptera: Braconidae) Ilgoo Kang, Joseph McCarthy, Forest Huval and Chris Carlton Description Sugarcane borer red-tailed braconids are specific parasitoids of sugarcane borer (Diatraea saccharalis) The sugarcane borer red-tailed braconid is a caterpillars and larvae of similar, closely related borer parasitoid wasp of the family Braconidae. Parasitoids are a species. Sugarcane borers and related species are pests of category of parasites that rely on a host during a certain sugarcane and other grass crops that spend most of their life stage (egg, larva or adult). They differ from other lives feeding inside stalks. The braconid females deposit parasites in that they always kill their hosts. eggs into sugarcane borer caterpillars inside the stalks. The adult sugarcane borer red-tailed braconid is about three-eighths of an inch (9 mm) in length with a black head, reddish orange and black thorax, and an orange abdomen. Their transparent wings are tinged dark brown and possess a small yellow spot on the front edge of each forewing. Males and females are similar except for the long egg-laying organs (ovipositors) of the females, which are almost as long as their bodies. Larvae are internal parasitoids and are almost never seen unless the host is dissected. They are soft bodied, legless and grublike. Many members of this family bear similar color patterns, so this species is sometimes confused with other braconid wasps. The sugarcane borer red-tailed braconid can most easily be distinguished from similar Dorsal view of the Alabagrus stigma, adult female braconid wasps by comparing their body ratio; members (preserved specimen, Louisiana State Arthropod Museum) of this species have relatively long, slender bodies with long ovipositors, while other members of the family have shorter, wider bodies with short ovipositors. Life History Many parasitoids specialize on a single host species or a group of closely related species, while some are less picky, parasitizing a variety of less closely related species. Often their hosts are the eggs or larvae of other insects, the most vulnerable life stages. A female finds a host and uses her ovipositor to deposit eggs onto or inside the body. The larvae hatch from the eggs, consume their hosts from the inside and eventually pupate. This process always kills the host. Lateral view of the Alabagrus stigma, adult female (preserved specimen, Louisiana State Arthropod Museum). Visit our website: www.LSUAgCenter.com The wasp larva emerges from the caterpillar just before it References pupates, eventually killing it as the wasp larva continues to Jaynes, H. A., 1938. Introduction and recovery in consume it. Once the caterpillar is dead, the wasp spins a Florida and Louisiana of parasites of the sugarcane borer. cocoon and, after several days, emerges as an adult. Journal of Economic Entomology 31: 93-95. Meagher Jr, R. L., Smith Jr, J. W., Browning, H. W. and R. Ecological Significance R. Saldana. 1998. Sugarcane stemborers and their parasites Wasps are considered aggressive insects by many in southern Texas. Environmental Entomology 27: 759-766. people. However, many wasps actually help farmers Sharkey, M. J., Meierotto, S., Chapman, E., Janzen, D. H., manage serious insect pests and are used as a form of Hallwachs, W., Dapkey, T. and Solis, M. Alma. 2018. Alabagrus biocontrol. In the case of the sugarcane borer red-tailed Enderlein (Hymenoptera, Braconidae, Agathidinae) species braconid, their parasitoid habits reduce the number of of Costa Rica, with an emphasis on specimens reared pests on two economically important crops in Louisiana, from caterpillars in Area de Conservación Guanacaste. rice and sugarcane. Because many parasitoid wasps are Contributions in Science 526: 31-180. specific to particular pest species, they have been utilized in biological control and integrated pest management applications around the world. The sugarcane borer red-tailed braconids were introduced as biocontrol agents to Louisiana during 1931. They were originally found by H. A. Jaynes in Peru during 1928 and have been used to help manage sugarcane borer Contact Us populations ever since. Because the wasps effectively For advice about arthropod identification or kill sugarcane and rice pest caterpillars, they have been diagnosis, contact the LSU AgCenter Department of used in rice fields throughout southeastern states, Entomology. Reach the department through the Contact especially Florida, Louisiana and Texas. Recently, the rice Us webpage: pest management lab in the LSU AgCenter Department https://bit.ly/36c4awm of the Entomology discovered that Mexican rice borers (Eoreuma loftini) are also parasitized by the sugarcane borer red-tailed braconids, so the species may have wider pest control applications in the future. Authors: Ilgoo Kang, Joseph McCarthy, Forest Huval and Chris Carlton William B. Richardson, LSU Vice President for Agriculture Louisiana State University Agricultural Center Louisiana Agricultural Experiment Station Louisiana Cooperative Extension Service LSU College of Agriculture PUB 3763 online 12/20 The LSU AgCenter and LSU provide equal opportunities in programs and employment. Visit our website: www.LSUAgCenter.com.